What Causes Dogs and Cats to Vomit?

Dog and cat vomiting can be caused by problems from within the stomach and intestines (called the gastrointestinal or GI tract) and by problems from outside the GI tract, such as kidney disease. Common causes of a dog or cat vomiting are allergies, illness, cancer, infections, drugs, parasites, plants, and poisons. Vomiting is also caused by incidents of overeating, foreign bodies, bloat (GDV or gastric dilatation volvulus), and constipation.
When your dog or cat vomits, he or she is ejecting food from the mouth that has been in the stomach. This can be a natural defense that protects your pet when he or she has eaten garbage, or it can be a sign of illness. Vomiting can be acute, meaning short-lived and over within hours, or it can be severe and last for days. With some pets, vomiting is chronic and lasts for months. Pets can vomit immediately after eating, or hours after eating if the food sits in the esophagus or stomach for hours. Pets tend to eject poisons quickly, but wait several hours before vomiting if the problem is an obstruction that prevents food from moving further down the intestinal tract.
The stomach's capacity is two to five ounces per pound, so a 50-pound Labrador Retriever may have almost a half gallon (eight cups) of stomach capacity. Thus, dogs can vomit an enormous amount, which often happens if they eat garbage. Dogs and cats can also vomit small amounts, especially if they have infections, liver disease, or kidney disease.

Key facts about vomiting in dogs and cats

• Regular dried dog and cat kibble is difficult for vomiting pets to digest.
• The stomach and intestines are called the gastrointestinal (GI) tract.
• Signs of nausea: listlessness, shivering, salivating, swallowing, lip-smacking, and hiding.
• Signs of dehydration: tacky mouth and gums, tented skin, sunken eyeballs.

Is my pet's vomiting dangerous?

Yes. Vomiting in cats and dogs is dangerous for many reasons. For example, pets that vomit lose fluids and electrolytes, such as sodium, potassium, and calcium. Without electrolytes, the brain, heart, and muscles stop working. Without fluids, pets become dehydrated and blood pressure falls. Without good blood pressure, the kidneys cannot produce urine, and harmful wastes collect in the body. Without fluids, the intestines don't function, so that your pet becomes constipated and strains to produce stool. In addition to these problems, pets that vomit may have material get sucked from the back of the throat into the lungs, causing fatal aspiration pneumonia.

Three stages to pet vomiting

1. Nausea
If your pet is nauseated, he or she may drool, swallow frequently, yawn, or smack his or her lips. Nauseated pets are often listless, and many prefer to hide.

2. Retching
Retching is when the stomach contracts and the muscles closing off the stomach don't relax so that nothing comes from the mouth.

3. Vomiting
Vomiting is when food is ejected from the mouth. Vomited food is partially digested and mixed with stomach acids. It is often soupy and may have dark coffee ground material, which is digested blood. If the vomit mixes with bile juices it will be yellow or greenish-brown.

Pink, Frothy "Vomit"
If the vomited material is pink, frothy fluid, it may actually have been coughed up from the lungs rather than vomited from the stomach. Frothy lung material can be white, pink (tinged with fresh blood) or brown (tinged with old blood). It will not be acidic. Pets with congestive heart failure, lung cancer, and some lung infections may cough up frothy material.

Regurgitation
Regurgitation is the release of food that was resting in the esophagus. When your pet regurgitates, he or she doesn't gag, retch, or feel nauseated. Female dogs regurgitate food for their pups. This is normal. If your pet regurgitates and is not feeding puppies, this is abnormal.
Some pets wait for hours after eating to regurgitate because the lower esophagus is dilated and holds a large amount of food. You can tell the difference between regurgitated and vomited food because regurgitated food is not acidic and it is never mixed with green or brown bile acids.

Distinguishing whether your pet's food is vomited or regurgitated
Problems that cause vomiting are different from problems that cause regurgitation. Regurgitation is caused by problems within the esophagus or by problems with the muscles that contract to move food down the esophagus. Among the causes of regurgitation are hernias, esophagitis, esophageal foreign body, esophageal stricture, megaesophagus, thyroid disease, polymyositis, immune-mediated disease, and myasthenia gravis.

Which pets are most at risk for vomiting?

Pets most likely to vomit include those that scavenge garbage, find poisons, have food allergies, worms, infections, or cancer.
Several breeds are predisposed to vomit because they have deep chests with large space for the stomach to swing within. A stomach full of food, fluid, or gas can swing and twist, creating a condition called bloat. With bloat, which is also called GDV or gastric dilatation volvulus, nothing can get beyond the twisted portion, and your dog vomits, but gas and food trapped below the twist are stuck. Bloat is often fatal, and even with emergency veterinary care, about one-third of pets with bloat die. The incidence of bloat is decreased if pets are fed two moist meals a day rather than one large meal of dry dog food. The incidence of bloat is also decreased if pets are not allowed to exercise for two hours after eating. Breeds prone to bloat include the Alaskan Malamute, Doberman Pinscher, German Shepherd, Gordon Setter, Great Dane, Irish Setter, Irish Wolfhound, Rottweiler, Standard Poodle, and Saint Bernard.
Breeds predisposed to vomit because they have cancer: Boxer, Boston Terrier, Beagle, Bulldog, Basset Hound, Saint Bernard, Golden Retriever, German Shepherd, Shetland Sheepdog, Poodle, Rottweiler, Airedale, Scottish Terrier, Cocker Spaniel, Doberman Pinscher, Miniature Schnauzer, and Shih Tzu. Siamese cats are also prone to cancer.
Breeds prone to vomit because they have Myasthenia Gravis, a paralyzing disease of nerves and muscles: Jack Russell, Springer Spaniel, Fox Terrier, Golden Retriever, German Shepherd, Labrador Retriever, Dachshund, and Scottish Terrier.
Breeds prone to vomit because they have polymyositis (poly meaning "many" and myositis meaning "inflamed muscle"), which causes pets to vomit because esophageal muscles don't work, are Collies and Shetland Sheepdogs.

Breeds predisposed to regurgitation

Some breeds are predisposed to regurgitation, often because they have an abnormal esophagus that balloons out (megaesophagus): Miniature Schnauzer, Wire-Haired Fox Terrier, Shar Pei, German Shepherd, Great Dane, Irish Setter, Labrador Retriever, and Newfoundland. Siamese cats are also more prone to regurgitate than other cat breeds.

Do all animals vomit?

No. Horses, rabbits, and rats are types of animals that don't vomit. These animals don't vomit because the sphincter muscles that close off the opening to the stomach are extraordinarily strong.